| Stage | Process | Tcore,min | Mstar,min | Time | Notes |
|---|---|---|---|---|---|
| D | 2H + 1H -> 3He + gamma | 1.0 x 106 K | ~ 0.013 MSun | ?? | Protostar -> Main Seq. or Brown Dwarf -> H WD? |
| Li | 6Li + 2 1H -> 2 4He | 2.5 x 106 K | ~ 0.06 MSun | ?? | |
| p+p | 4 1H -> 4He | 4.0 x 106 K | ~ 0.08 MSun | Main Seq. | Low-mass star -> He WD |
| CNO | 12C + 4 1H -> 12C + 4He | 1.8 x 107 K* | ~ 2 MSun | *dominant above this T | |
| 3-alpha | 3 4He -> 12C | 1.0 x 108 K | ~ 0.5 MSun | Horiz. Br. | Solar-type -> CO WD |
| ?? | 4He + 12C -> 16O | more at higher T | |||
| C | 12C + 12C -> 20Ne + 4He | 6.0 x 108 K | ~ 8 MSun | 500 yr | High-mass -> O/Ne/Mg WD? (or core collapse, SN II; many uncertainties) |
| 12C + 12C -> 23Na + 1H | |||||
| 12C + 12C -> 23Mg + n | |||||
| Ne | 20Ne + gamma* -> 16O + 4He | 1.2 x 109 K | ~ 10 - 11 MSun | 1 yr | *photodisintegration frees 4He |
| 20Ne + 4He -> 24Mg + gamma | SN II unavoidable? (mass loss dependence, envelope hides things, changes are quick + hard to model, few stars are in the right stage to observe) | ||||
| O | 16O + 16O -> 28Si + 4He | 1.5 - 2.0 x 109 K | 6 mo | ||
| Mg | 24Mg + 4He -> 28Si | ?? | ?? | ||
| Si | 28Si -> 56Fe (messy) | 2.7 - 3.5 x 109 K | 1 day | ||
| r-proc | 56Fe -> 238U, etc. | ?? | ~ 10 - 11 MSun | 1 sec | SN II -> NS/BH, depending on mass |